Abbott Sales Rise 5.8%; Mylan Terms Revised

Company Also Narrows its Earnings Guidance for the Year

Abbott Laboratories tweaked the terms of its agreement to sell a portion of its generic-drugs business to Mylan Inc. for $5.3 billion, signaling the deal will be completed despite new Treasury Department rules aimed at deterring tax-lowering mergers.

The companies said in July that Mylan would buy Abbott’s drug portfolio in developed overseas markets, enabling Mylan to benefit from a lower tax rate by organizing the new company in the Netherlands. But the new U.S. Treasury rules, enacted in response to a wave of...